"I think she would have to win the Geelong Cup or the Bendigo Cup next week, she'll have to win a race," O'Sullivan said of the mare's chances of making it to the Melbourne Cup.
"She would need to get a penalty, that's what I'd be hoping for."
O'Sullivan scratched Exceptionally from the Bart Cummings Stakes (2500m) during the Flemington race meeting on October 6 as he believed the track was too firm for the mare.
Exceptionally had her most recent start a week after her Flemington scratching and finished third in the Herbert Power Stakes (2400m) at Caulfield behind Shahwardi.
"The mare couldn't be doing better," O'Sullivan said.
Having been beaten by Shahwardi and having watched the Caulfield Cup performance of Dunaden, O'Sullivan knows the international horses will be a force to be reckoned with in the Geelong Cup.
Americain and Dunaden have won the Geelong Cup on their way to Melbourne Cup success in the past two years. "They are very good horses, there's no doubt about that," he said of the internationals.
"I'm not in any way saying she's better than them but with luck I think she can be pretty competitive."
- AAP